April 6 (Reuters) - U.S. stocks rose on Wednesday, bolstered by gains in healthcare shares after the collapse of the $160 billion merger of Pfizer and Allergan, and by a rise in energy shares.

Indexes slightly pared gains after the release of minutes from the most recent Federal Reserve meeting. They showed policymakers debated last month whether an interest rate hike would be needed in April, though a consensus emerged that risks from a global economic slowdown warranted a cautious approach.

“The minutes were a little more hawkish than the tone that we’ve heard from (Fed Chair Janet) Yellen post-FOMC meeting, but that was to be expected somewhat in my view,” said Scott Smith, senior market analyst at Cambridge global Payments in Toronto.

Investors have been grappling with mixed signals from Fed officials, including comments from Yellen last week that eased anxiety about potential interest rate hikes.

The collapse of the Pfizer and Allergan merger bolstered the healthcare sector on hopes that the pharmaceutical giants could turn to smaller targets.

Pfizer shares rose 3.9 percent to $32.57 and gave the biggest boost to the S&P 500, while Allergan was up 3.6 percent at $245.05. The S&P healthcare index was up 2.2 percent, while the Nasdaq Biotech Index jumped 4.8 percent.

At 2:52 p.m. the Dow Jones industrial average was up 28.39 points, or 0.16 percent, to 17,631.71, the S&P 500 gained 10.61 points, or 0.52 percent, to 2,055.78 and the Nasdaq Composite added 47.28 points, or 0.98 percent, to 4,891.21.

Crude jumped after data showed an unexpected draw in U.S. crude stockpiles last week, boosting shares of energy companies.

Advancing issues outnumbered declining ones on the NYSE by 1,898 to 1,074, for a 1.77-to-1 ratio on the upside; on the Nasdaq, 1,748 issues rose and 991 fell for a 1.76-to-1 ratio favoring advancers.

The S&P 500 posted 10 new 52-week highs and no new lows; the Nasdaq recorded 29 new highs and 18 new lows. (Additional reporting by Dion Rabouin in New York and Abhiram Nandakumar in Bengaluru; Editing by Anil D’Silva and Nick Zieminski)